Custom turbo
Custom turbo
09-09-2020, 04:27 PM
#9
(09-02-2020, 09:45 PM)Austincarnut(08-31-2020, 10:55 AM)OM616(08-27-2020, 05:54 PM)Austincarnut I was running no more than 1100*F going up hill with ac on at full boost on a hot day
Valve seat spring pressure has a lot to do with valve cooling. As boost (for intakes) EMP (for exhaust) pressure increases effective seat pressure decreases.
Additionally, if the spring pressure is not enough, the valve will bounce on the seat which significantly reduces the cooling of the valve which can result in the valve sinking or dishing. As far as I know, the OM61X engines redline is around 4500 ish at only 10/12 PSI of boost which on a stock T3 would generate around 15lbs of EMP. And that is will very little fueling. It sounds like you have increased fueling, boost, EMP, and RPM enough to push the valvetraine beyond its working range.
Valve cooling is all about seat pressure, and in really extreme set ups, seat material. Springs need to matched to suit the cam profile, boost, EMP, and RPM range.
Another thing I have seen is the valve nuts coming loose.
Hence my question. What will you do to your to avoid this? there is little to no room for adjusting spring pressure / valve geometry. I'm going to govern my max RPM for now.
I will definitely be using stronger springs to compensate for the 30-40 lbs of boost and corresponding EMP but I do not plan on spinning it up beyond 5K, don't see the need to.
I am going back and forth on having a steel cam made to my specks and make new roller tip rockers, or run the stock cam and make higher ratio rockers. I have advanced the cam as much as i can with the stock piston valve pockets, and I want to go another 7* so I have to cut the pockets deeper when i have the head off.
Out of curiosity, how fast were you spinning it???
(09-02-2020, 09:45 PM)Austincarnut(08-31-2020, 10:55 AM)OM616(08-27-2020, 05:54 PM)Austincarnut I was running no more than 1100*F going up hill with ac on at full boost on a hot day
Valve seat spring pressure has a lot to do with valve cooling. As boost (for intakes) EMP (for exhaust) pressure increases effective seat pressure decreases.
Additionally, if the spring pressure is not enough, the valve will bounce on the seat which significantly reduces the cooling of the valve which can result in the valve sinking or dishing. As far as I know, the OM61X engines redline is around 4500 ish at only 10/12 PSI of boost which on a stock T3 would generate around 15lbs of EMP. And that is will very little fueling. It sounds like you have increased fueling, boost, EMP, and RPM enough to push the valvetraine beyond its working range.
Valve cooling is all about seat pressure, and in really extreme set ups, seat material. Springs need to matched to suit the cam profile, boost, EMP, and RPM range.
Another thing I have seen is the valve nuts coming loose.
Hence my question. What will you do to your to avoid this? there is little to no room for adjusting spring pressure / valve geometry. I'm going to govern my max RPM for now.
I will definitely be using stronger springs to compensate for the 30-40 lbs of boost and corresponding EMP but I do not plan on spinning it up beyond 5K, don't see the need to.
I am going back and forth on having a steel cam made to my specks and make new roller tip rockers, or run the stock cam and make higher ratio rockers. I have advanced the cam as much as i can with the stock piston valve pockets, and I want to go another 7* so I have to cut the pockets deeper when i have the head off.
Out of curiosity, how fast were you spinning it???
Messages In This Thread
Custom turbo - by OM616 - 07-29-2020, 01:46 PM
RE: Custom turbo - by Austincarnut - 07-29-2020, 10:07 PM
RE: Custom turbo - by OM616 - 07-30-2020, 01:27 PM
RE: Custom turbo - by Austincarnut - 08-10-2020, 09:30 PM
RE: Custom turbo - by OM616 - 08-11-2020, 09:27 AM
RE: Custom turbo - by Austincarnut - 08-27-2020, 05:54 PM
RE: Custom turbo - by OM616 - 08-31-2020, 10:55 AM
RE: Custom turbo - by Austincarnut - 09-02-2020, 09:45 PM
RE: Custom turbo - by OM616 - 09-09-2020, 04:27 PM
RE: Custom turbo - by vica153 - 09-30-2020, 11:09 PM
RE: Custom turbo - by OM616 - 10-02-2020, 05:21 PM
RE: Custom turbo - by vica153 - 10-02-2020, 08:29 PM
RE: Custom turbo - by OM616 - 10-03-2020, 04:08 PM
RE: Custom turbo - by vica153 - 10-04-2020, 12:25 AM
RE: Custom turbo - by OM616 - 10-04-2020, 12:08 PM
RE: Custom turbo - by vica153 - 10-04-2020, 02:01 PM
RE: Custom turbo - by OM616 - 10-04-2020, 06:28 PM
RE: Custom turbo - by vica153 - 10-04-2020, 08:40 PM
RE: Custom turbo - by vica153 - 10-04-2020, 08:52 PM
RE: Custom turbo - by 50harleyrider - 10-11-2020, 09:11 PM
RE: Custom turbo - by vica153 - 10-11-2020, 11:39 PM
RE: Custom turbo - by OM616 - 12-06-2020, 02:11 PM
Users browsing this thread:
2 Guest(s)
2 Guest(s)
Users browsing this thread:
2 Guest(s)
2 Guest(s)